The present invention relates to a head of an ultrasonic wire bonding apparatus utilizing the vibration of a capillary by ultrasonic waves and a method for carrying out the bonding operation.
A conventional ultrasonic wire bonding apparatus using the vertical vibration is shown in FIG. 9. In the apparatus of FIG. 9, a capillary 2 is fixed perpendicularly to a horn 1 which vibrates in the vertical direction. A lead wire 6 is pressed to a bare chip 4 and a lead frame 5 placed on a work table 3 by the capillary 2 to which a minute pressure is applied. While the horn 1 is vibrated vertically by the ultrasonic waves, the bare chip 4 and the lead frame 5 are bonded by the lead wire 6.
In the above-described constitution, the size of the work table 3 for bonding is restricted depending on the length of the horn 1 due to the interference therebetween. Therefore, if the horn is elongated to widen the bonding range, the horn is bent and deflected. As a result, the horn starts vibrating up and down, which causes the damage of the bare chip. The bonding range is therefore impossible to be made wide in the conventional arrangement.